Field of the Invention
The present invention relates to a fan-blade axial locking device.
Summary of the Prior Art
In order to provide for the axial locking of blades on a rotor disc of a gas turbine, various devices are known.
U.S. Pat. No. 4,033,785 relates to a device in which the rotor disc comprises at its periphery teeth having radial recesses disposed one facing the other and in which is engaged a locking member in the form of a dovetail against which abuts through a resilient member the root of the blade, the said locking member having feet which abut against an annular ring secured on the upstream face of the disc. Such a device has, however, a degree of complexity which gives rise to a high manufacturing cost of the parts by which it is formed.
Nevertheless, rapid disassembly and location of a single blade is impossible with this device, since it requires that all the fixing pins of the flanges of the annular ring need to be withdrawn.
U.S. Pat. No. 3,656,865 relates to a locking device for blades comprising a plurality of retention plates located in a groove of the teeth of the disc; a claw of the foot of the blade preventing axial movement from upstream in the downstream direction.
However, in this proposal, the retention plate is located in a closed circumferential groove in the direction of the centre and not in radial slots open in the direction of the centre.
Furthermore, the retention plate requires for securing in place a second circumferential groove provided in a collar at the upstream face of the disc.
The introduction or the retraction of the retaining plate in the grooves is effected by deformation, which prevents the use of a thick plate and has a strength equal to that which is desired.
French Pat. Nos. 2 013 647 and 2 345 605 relate to a device in which the root of the blade carries a nose which is provided with radial slots corresponding to the grooves of the teeth and in which is engaged a locking member of U-shape. Locking is thus not provided by simple abutment against the root of the blade.
The present invention has for its object to overcome these disadvantages and to provide a simple device enabling the disassembly and the reassembly separately for each of the blades.